Rear projection type liquid crystal TV sets and liquid crystal projectors are spreading both for commercial and domestic purposes. They are projection type display apparatuses which have a light source, e.g., ultra-high pressure mercury lamp, emitting light of high intensity to display projected images on a screen via a display device, e.g., liquid crystal display device.
For such a projection type display apparatus to keep image brightness for extended periods, it is essential that it has a light source serviceable for extended periods and, at the same time, a mirror as a reflector stably keeping reflection for effectively deflecting emitted light forward. A reflector should reflect light emitted from a light source in an adequate direction. Therefore, it is required to have high molding precision of a reflector and reliability of resistance to environment of its reflection film, among others. A lamp mounted on, or placed near, a reflector reaches a high temperature when it works continuously, and is cooled by a cooling fan or the like. Nevertheless, the reflector is required to be heat-resistant, because of a fairly large quantity of heat generated by the lamp. A silver or silver alloy layer, which has high reflectivity, can be formed by spraying an electroless plating solution without needing a vacuum process. Thus, coating a reflector with silver or a silver alloy layer brings a merit of dispensing with a vacuum process.
Patent Document described below discloses coating with a top coat layer as one of the techniques for preventing corrosion of a reflection layer of silver or the like.    Patent Document 1: JP-A-2002-256455